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Sodium thiosulfate content
Sodium thiosulfate content, Total:224 items.
In the international standard classification, Sodium thiosulfate content involves: Pulps, Non-ferrous metals, Inorganic chemicals, Analytical chemistry, Photography, Metalliferous minerals, Rubber, Non-metalliferous minerals, Organic chemicals, Products of the chemical industry, Spices and condiments. Food additives, Wastes, Ferrous metals, Iron and steel products, Leather technology, Paint ingredients, Testing of metals, Ferroalloys.
Association Francaise de Normalisation, Sodium thiosulfate content
- NF Q50-005:1967 PULPS FOR PAPER. QUANTITY DETERMINATION OF SODIUM THIOSULPHATE IN PULP LIQUORS FOR PAPERMAKING.
- NF T20-459:1980 Sodium sulphate for industrial use. Determination of sodium sulphate content. Gravimetric method.
- NF T20-454:1976 Sodium sulphate for industrial use. Determination of sulphate content. Calculation method and barium sulphate gravimetric method.
- NF T20-417:1975 Sodium carbonate for industrial use. Determination of sulphate content. Barium sulphate gravimetric method.
- NF T29-002:1968 Produits chimiques destinés à la photographie - Thiosulfate de sodium cristallisé.
- NF T20-405:1982 Sodium chloride for industrial use. Determination of sulphate content. Barium sulphate gravimetric method.
- NF T20-527:1980 Sodium and potassium silicates for industrial use. Determination of sulphates content. Barium sulphate gravimetric method.
- NF T20-429:1976 Sodium hydroxyde for industrial use. Determination of sulphate content. Barium sulphate gravimetric method.
- NF T94-210:2005 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate.
- NF T94-210*NF EN 12125:2013 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
- NF EN 16399:2014 Produits chimiques utilisés pour le traitement de l'eau des piscines - Thiosulfate de sodium
- NF U42-178*NF EN 15960:2012 Fertilizers - Extraction of total calcium, total magnesium, total sodium and total sulfur in the forms of sulfates
- NF Q50-004:1966 PULPS FOR PAPER. QUANTITY DETERMINATION OF SODIUM SULPHIDE IN PULP LIQUORS FOR PAPERMAKING.
- NF T94-449*NF EN 16399:2014 Chemicals used for treatment of swimming pool water - Sodium thiosulfate
- NF T20-364:1978 Potassium sulphate for industrial use. Determination of sulphate content.baryum sulphate gravimetric method.
- NF G52-218:1982 Chemical analysis of leather. Determination of sodium sulphate content.
- NF EN 12125:2022 Produits chimiques utilisés pour le traitement de l'eau destinée à la consommation humaine - Thiosulfate de sodium
- NF T20-453:1976 Sodium sulphate for industrial use. Determination of chlorides content. Mercurimetric method.
- NF T20-298:1982 Sulphuric acid for industrial use. Determination of arsenic content. Silver diethyldithiocarbamate photometric method.
Professional Standard - Commodity Inspection, Sodium thiosulfate content
- SN/T 4376-2015 Copper and copper alloy scraps.Determination of copper content.Titration method of sodium hyposulfite
- SN/T 3927-2014 Determination of sodium thiocyanate in dairy products for export
Professional Standard - Non-ferrous Metal, Sodium thiosulfate content
- YS/T 807.12-2012 Chemical analysis methods of aluminum hardeners.Part 12:Determination of copper content.Sulfur and sodium titration method
- YS/T 226.15-1994 Determination of selenium content in selenium (sodium thiosulfate volumetric method)
- YS/T 539.9-2006 Nickel-based alloy powder chemical analysis method sodium thiosulfate-iodometric method for determination of copper content
- YS/T 252.4-2007 Methods for chemical analysis of nickel matte.Determination of copper content.Sodium thiosulphate titrimetric method
- YS/T 226.12-2009 Methods for chemical analysis of selenium.Part 12:Determination of selenium content.Sodium thiosulphate titrimetric method
- YS/T 475.4-2005 Methods for chemical analysis of cast bearing metals-Determination of copper content-Hyposulphite titrimetric method
- YS/T 716.1-2009 Methods for chemical analysis of low grade blister.Part 1:The determination of copper content.Sodium hyposulfite titration
- YS/T 539.9-2009 Methods for chemical analysis of nickel base alloy powder.Part 9:Determination of copper content.Thiosulfate iodimetry
Korean Agency for Technology and Standards (KATS), Sodium thiosulfate content
CZ-CSN, Sodium thiosulfate content
HU-MSZT, Sodium thiosulfate content
Japanese Industrial Standards Committee (JISC), Sodium thiosulfate content
General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China, Sodium thiosulfate content
- GB/T 637-2006 Chemical reagent Sodium thiosulfate pentahydrate
- GB/T 22402-2008 Photography.Processing chemicals.Specifications for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate
- GB 637-1988 Chemical reagent Sodium thiosulfate pentahydrate
- GB/T 637-1988 Chemical reagent--Sodium thiosulfate pentahydrate
- GB/T 3514-1992 Rubber,Vulcanized-dtermination of free sulphur content Sodium sulphite method
- GB/T 13530.2-1992 Sodium ethoxylated alkyl sulfate--Determination of unsulfated matter content
- GB/T 11213.5-1989 Sodium hydroxide for chemical fiber use--Determination of sulphate mass fraction--Barium sulphate gravimetric method
- GB/T 8638.9-1988 Nickel base alloy powder--Determination of copper content--Thiosulfate-iodimetric method
- GB 223.18-1982 Chemical analysis of iron,steel and alloy--The determination of copper by thiosulfate-iodide method
- GB/T 11213.5-2006 Sodium hydroxide for chemical fiber use.Determination of sulphate content
- GB/T 223.18-1994 Methods for chemical analysis of iron steel and alloy.The sodium thiosulfate separation iodimetric method for the determination of cupper content
- GB/T 11198.1-1989 Sulphuric acid for industrial use--Determination of sulphuric acid content and calculation of free sulphur trioxide content of oleum--Titrimetric method
- GB 4581.4-1984 Alunite ores--Determination of sulphur content for sulphate--Barium sulphate gravimetric method
- GB/T 11198.5-1989 Sulphuric acid for industrial use--Determination of arsenic content--Silver diethyldithiocarbamate photometric method
- GB/T 6730.16-2016(英文版) Iron ores—Determination of sulfur content—Barium sulfate gravimetric method
- GB/T 13248-1991 Vulcanized rubber--Determination of manganese content--Sodium periodate photometric methods
- GB/T 13530.1-1992 Sodium ethoxylated alkyl sulfate--Determination of total active matter content
Professional Standard - Chemical Industry, Sodium thiosulfate content
- HG/T 2328-2006 Sodium hyposulfite for industry use
- HG/T 2328-1992 Industrial sodium thiosulfate
- HGB 3494-1962 Sodium Diethylaminothioformate
- HG/T 2964-1984 Sodium hydrosulphide for industrial use-Determination of the content of sodium hydrosulphide ane sulphide
- HG/T 2957.4-1984(1997) Alunite ores-Determination of sulphur content for sulphate-Barium sulphate gravimetric method
- HG/T 2957.4-2004 Determination of sulfate sulfur content in alunite ore barium sulfate gravimetric method
International Organization for Standardization (ISO), Sodium thiosulfate content
- ISO 5142:1977 Sodium sulphate for industrial use; Determination of sodium sulphate content; Gravimetric method
- ISO 10636:1994 Photography; processing chemicals; specifications for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate
- ISO 3237:1975 Sodium sulphate for industrial use; Determination of sulphates content; Calculation method and barium sulphate gravimetric method
- ISO 743:1976 Sodium carbonate for industrial use; Determination of sulphate content; Barium sulphate gravimetric method
- ISO 3300:1976 Photographic grade sodium thiosulphate, anhydrous; Specification
- ISO 419:1972 Photographic grade sodium thiosulphate, crystalline; Specification
- ISO 982:1976 Sodium hydroxide for industrial use — Determination of sulphate content — Barium sulphate gravimetric method
- ISO 2480:1972 Sodium chloride for industrial use; Determination of sulphate content; Barium sulphate gravimetric method
- ISO 3200:1975 Sodium and potassium silicates for industrial use; Determination of sulphates content; Barium sulphate gravimetric method
- ISO 3236:1975 Sodium sulphate for industrial use — Determination of chlorides content — Mercurimetric method
- ISO 2487:1973 Potassium sulphate for industrial use; Determination of sulphate content; Barium sulphate gravimetric method
- ISO 2486:1973 Potassium sulphate for industrial use — Determination of potassium content — Sodium tetraphenylborate volumetric method
- ISO 5792:1978 Sulphuric acid for industrial use; Determination of arsenic content; Silver diethyldithiocarbamate photometric method
- ISO 3423:1975 Sulphuric acid and oleums for industrial use; Determination of sulphur dioxide content; Iodometric method
- ISO 906:1976 Hydrochloric acid for industrial use; Determination of sulphate content; Barium sulphate gravimetric method
- ISO 5786:1978 Ammonium sulphate for industrial use; Determination of arsenic content; Silver diethyldithiocarbamate photometric method
- ISO 3333:1975 Ammonium sulphate for industrial use; Determination of copper content; Zinc dibenzyldithiocarbamate photometric method
American National Standards Institute (ANSI), Sodium thiosulfate content
- ANSI PH4.250-1980 Photographic Grade Sodium Thiosulfate, Anhydrous (Na2S2O3) and Sodium Thiosulfate, Crystalline (Na2S2O3. 5H2O)
Taiwan Provincial Standard of the People's Republic of China, Sodium thiosulfate content
- CNS 1421-1962 Sodium Thiosulfate (Industrial Grade)
- CNS 1993-1978 Sodium Thiosulfate
- CNS 5152-1980 Crystalline Sodium Thiosulphate (Photographic Grade)
- CNS 8043-1981 Method for Determination of Copper in Ores (Sodium Thiosulfate Titration Method)
- CNS 8046-1981 Method for Determination of Copper in Iron Ores (Sodium Thiosulfate Titration Method)
- CNS 1422-1962 Method of Test for Sodium Thiosulfate of Industrial Grade
- CNS 1991-1978 Sodium Thiocyanate (Sodium Sulfocyanate)
- CNS 4634-1978 Rubber Vulcanization Accelerator NaBDC (Sodium Di-n-Butyl Dithiocarbamate Solution)
British Standards Institution (BSI), Sodium thiosulfate content
- BS ISO 10636:1994 Photography. Processing chemicals. Specification for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate
- BS ISO 10636:1995 Photography - Processing chemicals - Specification for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate
- BS EN 16399:2013 Chemicals used for treatment of swimming pool water. Sodium thiosulfate
- BS EN 12125:2005 Chemicals used for treatment of water intended for human consumption — Sodium thiosulfate
- BS EN 12125:2012 Chemicals used for treatment of water intended for human consumption. Sodium thiosulfate
- BS EN 12125:2006 Chemicals used for treatment of water intended for human consumption. Sodium thiosulfate
- PD ISO/TS 4689-1:2023 Iron ores. Determination of sulfur content. Barium sulfate gravimetric method
Indonesia Standards, Sodium thiosulfate content
- SNI 06-1314-1989 Technical grade sodium thiosulphate
- SNI 06-4987-1999 Method for production of standard sodium thiosulphate 0.1 N solutions and method for standardization
PK-PSQCA, Sodium thiosulfate content
- PS 443-1975 SPECIFICATION FOR SODIUM THIOSULPHATE (REVISED)
RO-ASRO, Sodium thiosulfate content
- STAS 1817/2-1975 SODIUMTHIOSULFATE, TECHNICAL GRADE
- STAS 1817/3-1974 SODIUM THIOSULFATE Methods of analysis
- STAS SR 13371-1997 Sodium chloride. Determination of total iodine. Titrimetric Method with sodium thiosulfate
- STAS SR ISO 2480:1995 Sodium chloride for industrial use. Determination of sulphate content. Barium sulphate gravimetric method
- STAS 1817/1-1975 CRYSTALLIZED SODIUM THIOSULPHATE, PHOTOGRAP- HIGAL AND CINEMATOGRAPHICAL GRADE
- STAS 12873-1990 Cinematograph. Residual thiosulphate determination
- STAS 8934/12-1979 SALT (SODIUM CHLORIDE) Determination of suphate ions content
- STAS 4605/13-1972 NON-METAT, BEARING MIXIXG PRODUCTS WITH CARBONATE CONTENT DCtermination of sulphate ion and tolal sulphur
RU-GOST R, Sodium thiosulfate content
- GOST 244-1976 Sodium thiosulphate, crystalline. Specifications
- GOST 27068-1986 Reagents. Sodium thiosulphate 5-aqueous. Specifications
- GOST R 51575-2000 Food common salt with content of iodine. Methods for determination of iodine and sodium thiosulphate
AENOR, Sodium thiosulfate content
- UNE 30189:1963 ANALYSIS REAGENTS. SODIUM THIOSULPHATE.
- UNE 34233:1984 SODIUM CHLORIDE. DETERMINATION OF SULPHATE CONTENT. BARIUM SULPHATE GRAVIMETRIC METHOD.
- UNE-EN 16399:2014 Chemicals used for treatment of swimming pool water - Sodium thiosulfate
- UNE 55504-3:1981 SURFACE ACTIVE AGENTS. ANALYSIS OF TECHNICAL SODIUM SEC-ALKYLSULPHATES. DETERMINATION OF THE SODIUM SEC-ALKYLSULPHATES CONTENT
- UNE-EN 12125:2013 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
- UNE 22138:1990 IRON ORES. DETERMINATION OF SULFUR CONTENT. BARIUM SULFATE GRAVIMETRIC METHOD
未注明发布机构, Sodium thiosulfate content
- BS ISO 10636:1994(2000) Photography — Processingchemicals — Specifications for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate
AR-IRAM, Sodium thiosulfate content
KR-KS, Sodium thiosulfate content
- KS M ISO 10636-2019 Photography — Processing chemicals — Specifications for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate
- KS M ISO 2480-2017 Sodium chloride for industrial use — Determination of sulphate content — Barium sulphate gravimetric method
- KS M ISO 3705-2017 Sulphur for industrial use — Determination of arsenic content — Silver diethyldithiocarbamate photometric method
Group Standards of the People's Republic of China, Sodium thiosulfate content
- T/CSTM 00702-2022 Chemical reagent — Sodium thiosulfate anhydrous
- T/HATSI 0013-2021 Technical specification for separation and purification of sodium sulfite and sodium sulfate from arsenic containing mixed salt
IN-BIS, Sodium thiosulfate content
Professional Standard - Agriculture, Sodium thiosulfate content
- 2091药典 二部-2015 Sodium thiosulfate
- 2185药典 二部-2020 Sodium thiosulfate
- 1719药典 二部-2010 Sodium thiosulfate
- 2092药典 二部-2015 Part 12 Sodium Thiosulfate Injection
- 2186药典 二部-2020 Part 12 Sodium Thiosulfate Injection
- 1720药典 二部-2010 Part 12 Sodium Thiosulfate Injection
- 331兽药典 一部-2015 The first part of the text variety twelve strokes sodium thiosulfate
- 226药典 三部-2020 Content determination method 3105 sodium bisulfite determination method
- 179兽药产品说明书范本第一册-2013 Instructions for Twelve Draws Nitrothioquine Chloropus Sodium Thiosulfate Injection
- 199药典 四部-2015 3100 content determination method 3105 sodium bisulfite determination method
- 187药典 四部-2020 3100 content determination method 3105 sodium bisulfite determination method
- 332兽药典 一部-2015 Varieties of the main text Part 1: Sodium Thiosulphate Injection
- 207药典 三部-2015 Content determination method 3105 Sodium bisulfite determination method general rule 54
- 315兽药质量标准2017年版 Chemical Drugs Volume 1 Veterinary Drug Quality Standard 12 Sodium Thiosulfate Powder (for Aquaculture)
BELST, Sodium thiosulfate content
- STB GOST R 51575-2004 Food common salt with content of iodine. Methods for dеtеrminаtion of iodine and sodium thiosulfаtе
BE-NBN, Sodium thiosulfate content
- NBN T 03-179-1980 Sodium sulphate for industrial use - Determination of sodium sulphate content - Gravimetrie method
- NBN T 03-110-1979 Sodium carbonate for industrial use - Determination of sulphate content - Barium sulphate gravimetrie method
- NBN T 03-162-1980 Sodium chloride for industrial use - Determination of sulphate content - Barium sulphate gravimetrie method
- NBN T 03-124-1980 Sodium hydroxide for industrial use - Determination of sulphate content - Barium sulphate gravimetrie method
- NBN T 03-174-1980 Sodium sulphate for industrial use - Determination of sulphates content - Calculation method and barium sulphate gravimetric method
- NBN T 03-025-1979 Sulphuric acid and oleum for industrial use - Determination of sulphur dioxide content - Iodometric method
- NBN T 03-016-1979 Sulphuric acid and oleum for industrial use - Determination of total acidity, and calculation of free sulphure trioxide content of oleum - Titrimetric method
- NBN T 03-209-1980 Potassium sulphate for industrial use - Determination of sulphate content - Barium sulphate gravimetrie method
- NBN T 03-026-1979 Sulphuric acid for industrial use - Determination of arsenic content -Silver diethyldithiocarbamate photometric method
TR-TSE, Sodium thiosulfate content
- TS 757-1969 SODIUM CARBONATE FOR INDUSTRIAL USE DETERMINATION OF SULPHATE CONTENT BARIUM SULPHATE GRAVIMERTIC METHOD
- TS 2226-1976 SODIUM AND POTASSIUM SILICATES FOR INDUSTRIAL USE DETERMINATION OF SULPHATES CONTENT BARIUM SULPHATE GRAVIMETRIC METHOD
- TS 993-1971 SODIUM HYDROXIDE AND POTASSIUM HYDROXIDE FOR INDUSTRIAL USE DETERMINATION OF SULPHATE CONTENT (BARIUM SULPHATE GRAVIMETRIC METHOD
PL-PKN, Sodium thiosulfate content
- PN C84002-11-1988 Sodium hydroxide technical Determination of sodium sulphate content
- PN H04108-1993 Iron ores. Determination of sulfur content. Barium sulfate gravimetric method
YU-JUS, Sodium thiosulfate content
- JUS H.G8.421-1990 Reagents. Sodlum sulphite, anhydrous and sodium sulphite heptahydrate. Determinatlcm of substances insoluble in nater. Gravimstric ttethod
- JUS H.G8.033-1981 Reagents. Sulphuric acid. Determination of arsenic content Silver diethyldithiocarbamate photometric method
- JUS H.G8.426-1990 Reaqents. Sodiuin sulphite, anhvdrous, and sodium sulphite heptahydrate. Determination of lead, copper and calcium contents. Flame atomic absorption method
- JUS H.G8.080-1983 Reagents. Sodium chloride. Determination of sulphate content. Turbidimetric method
- JUS H.G8.376-1989 Reagents. Sodium acetate trihvdrate and sodlum acetate anhydrous. Determination of sulphates content. Turbidimetric method
- JUS H.G8.148-1985 Reagents.Ammonium sulphate. Determination of arsenic content Silver diethyldlthiocarbamate photo- metric method
- JUS H.B8.721-1981 Copper sulphate. Titrimetric determination of copper sulphate content
- JUS H.G8.427-1990 Reaaents. Sodium sulphite, anhvdrous and sodium sulphite heptahv?rate. Determination of arsenic content. Silver diethyldithiocarbamate spectrophotometric method
- JUS H.G8.452-1991 Reagents. Potassium sulpbate. Determination of potassium sulphate content. Volumetric method
- JUS H.B8.640-1981 Sulphuric acid and oleum for industrial use. Determination of sulphur dioxide content lodometric method
- JUS H.G8.139-1985 Peagents. Ammonium sulphate. Determination of ammonium sulphatecontent Volumetric method
- JUS H.G8.414-1991 Reagents. Sodium hydroxi?e. Determination of sulphates content. Turbidimetric method
- JUS H.B8.017-1981 Sutphuric acid and oleum for industrial use. Determination of lead content. Dithizone photometric method
- JUS H.G8.450-1990 Reagents. Zine sulphate heptahydrate- Determination of arsenic content. Silver diethvldithiocarbamate speetrophotometric method
- JUS H.B8.722-1981 Copper sulphate. Determination of iron content
European Committee for Standardization (CEN), Sodium thiosulfate content
- EN 12125:1998 Chemicals Used for Treatment of Water Intended for Human Consumption - Sodium Thiosulfate
- EN 12125:2012 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
- EN 16399:2013 Chemicals used for treatment of swimming pool water - Sodium thiosulfate
- EN 12926:2015 Chemicals used for treatment of water intended for human consumption - Sodium peroxodisulfate
CEN - European Committee for Standardization, Sodium thiosulfate content
- EN 12125:2005 Chemicals Used for Treatment of Water Intended for Human Consumption - Sodium Thiosulfate
IT-UNI, Sodium thiosulfate content
VN-TCVN, Sodium thiosulfate content
- TCVN 3799-1983 Sodium hydroxide technical.Method of test for sodium sulfate content
Lithuanian Standards Office , Sodium thiosulfate content
- LST ISO 2480:2003 Sodium chloride for industrial use. Determination of sulphate content. Barium sulphate gravimetric method (idt ISO 2480:1972)
- LST EN 12125-2013 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
German Institute for Standardization, Sodium thiosulfate content
- DIN EN 16399:2014-03 Chemicals used for treatment of swimming pool water - Sodium thiosulfate; German version EN 16399:2013
- DIN EN 12125:2022 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
- DIN EN 12125:2020 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate; German and English version prEN 12125:2020
- DIN EN 12125:2022-10 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate; German version EN 12125:2022 / Note: This standard is part of the DVGW body of rules.
- DIN EN 12125:2013 Chemicals used for treatment of water intended for human consumption.Sodium thiosulfate; German version EN 12125:2012
- DIN EN 16399:2014 Chemicals used for treatment of swimming pool water - Sodium thiosulfate; German version EN 16399:2013
Danish Standards Foundation, Sodium thiosulfate content
- DS/EN 12125:2013 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
- DS/EN 26595:1993 Water quality. Determination of total arsenic. Silver diethyldithiocarbamate spectrophotometric method
ES-UNE, Sodium thiosulfate content
- UNE-EN 12125:2022 Chemicals used for treatment of water intended for human consumption - Sodium thiosulfate
PT-IPQ, Sodium thiosulfate content
Qinghai Provincial Standard of the People's Republic of China, Sodium thiosulfate content
- DB63/T 1296-2014 Determination of sodium chloride and sulfate content in industrial sodium carbonate by ion chromatography
轻工业部, Sodium thiosulfate content
- QB 1035.4-1991 Determination of food additive sodium tripolyphosphate sulfate content
工业和信息化部, Sodium thiosulfate content
- YB/T 6013.1-2022 Determination of sulfate and sulfite content in sintering flue gas desulfurization ash. Barium sulfate gravimetric method.
中华人民共和国国家质量监督检验检疫总局、中国国家标准化管理委员会, Sodium thiosulfate content
- GB/T 33054-2016 Determination of content of sodium sulfide in sulphur dye products
- GB/T 6730.16-2016 Iron ores—Determination of sulfur content—Barium sulfate gravimetric method
Professional Standard - Light Industry, Sodium thiosulfate content
- QB/T 1035.4-1991 Food additive sodium tripolyphosphate sulfate content determination gravimetric method
ET-QSAE, Sodium thiosulfate content
Professional Standard - Ferrous Metallurgy, Sodium thiosulfate content
- YB/T 5040-2012 Molybdenum oxide.Determination of sulfur content.Gravimetric method of barium sulfate
Professional Standard - Machinery, Sodium thiosulfate content
- JB/T 9499.2-1999 Method for chemical analysis of constantan resistance alloy The potassium iodide - sodium thiosulfate titrimetric method for the determination of copper content